The present invention relates to thermal image processing devices, infrared imaging apparatuses, thermal image processing methods, and thermal image processing programs.
In recent years, a number of products that utilize an infrared camera provided with an infrared detector have been developed for security purpose or for use in mobile units. Infrared cameras detect heat in captured images and can thus detect humans and objects in an environment where no visible light is present, as in nighttime. The use of such a sensor in automobiles or the like, for example, makes it possible to detect humans or objects within a range which headlights do not reach at night. Then, the driver or the like is alerted to a possible human or object that may collide with the automobile or the like, thus helping to improve the safety of the automobile or the like.
Such infrared cameras are susceptible to influence of a change or the like in the environmental temperature, which causes their signals to deteriorate. Therefore, a measure is being taken to maintain a predetermined accuracy of the infrared cameras by calibrating output signals of the infrared cameras as appropriate. For example, an infrared imaging apparatus (Japanese Unexamined Patent Application Publication No. 2007-201807) includes a shutter that opens or closes an aperture for taking light into an infrared detector. The infrared imaging apparatus calculates an output value of each element of the infrared detector while the shutter is closed and also calculates an offset correction value of each element on the basis of the measured surface temperature of the shutter.